The formation of polychlorinated hydrocarbons containing three or more carbon atoms by the addition of a chlorinated alkane to an alkene is a process well documented in the art. For example, Wilson et al (U.S. Pat. No. 5,792,893) describe the manufacture of 1,1,1,3,3,3-hexachloropropane by the addition of carbon tetrachloride to 1,1-dichloroethene using a catalyst comprising copper and a solvent selected from a C3 to a C5 alkanenitrile. Wilson et al (U.S. Pat. No. 6,313,360) teach the manufacture of 1,1,1,3,3-pentachloropropane by the addition of carbon tetrachloride to vinyl chloride in the presence of a catalyst mixture comprising organophosphate solvent, iron metal and ferric chloride. These addition reactions in general are referred to as telomerization reactions.
While telomerization reactions can generally be made to proceed with high selectivity to the desired products, invariably some unwanted by-products are also produced. Sometimes an isomer of the desired polychlorinated alkane is formed. Heavy end by-products are usually present that result at least partially by the addition of the desired product with unreacted olefine feed still present in the reaction media. For example, in the production of 1,1,1,3,3,3-hexachloropropane by the addition of carbon tetrachloride to 1,1-dichloroethene, several percent 1,1,1,3,3,5,5,5-octachloropentane is also produced by the addition of the hexachloropropane to unreacted 1,1-dichloroethene. Similarly, in the production of 1,1,1,3,3-pentachloropropane by the addition of carbon tetrachloride to vinyl chloride, several percent 1,1,3,3,5,5- and 1,1,1,3,5,5-hexachloropentane are also formed. These compounds have higher boiling points than the desired products, and thus are typically removed from the process as heavy ends. Due to limitations in the distillation process, often some of the desired C3 or higher polychlorinated alkane product may also be present in this heavy ends stream. Normally, these heavy ends would be disposed of as waste by incineration or other environmentally acceptable methods, and thus are an inefficiency in the utilization of the starting materials.